Currently running a dual head twinview setup (primary screen on right and secondary on left). Both screens have identical resolutions (1680x1050) and i have meta modes for having dual screens, and then also having the left monitor(secondary) blank, with various resolutions on the primary monitor for gaming.

There are 2 bugs that seem to exhibit with this setup:

1. Any fullscreen game i try (urban terror, quake IV, various wine games) will cause the correct mode change (the secondary monitor goes off, and the primary switches to correct resolution), however the game starts half way across the monitor with half off screen, if i move mouse to the right it eventually uses fullscreen and stays that way (my current xorg.conf has metamodes with +0+0 but this also happens without that). This problem doesnt seem to occur when i have primary monitor on left, and secondary on the right. It also happens regardless of my DynamicTwinView setting.

2. Mouse movements seem very limited, there seem to be boundaries on how far i can turn before it stops working. For instance, i start a game of urban terror, and i can only turn right or left in approximately a 180 degree arc. Even in the menus i cant alwasy move mouse across the full screen. My current conf doesnt have a mouse section (auto detection seems to be working properly) but i would get the same behaviour with the default mouse section that ubuntu generates, and any variation using ImPS/2 and Explorer/PS2 for the protocol (evdev just locks X for some reason, but i doubt thats due to nvidia)

The xorg atatched in the log has gone through some changes, but both these problems exist regardless of anything i have been able to do.

I have the exact same problem as you when playing games fullscreen. They show up 1/2 across my primary monitor which is on the right. Opengl screensavers and amarok visualizations also have the same problem. The only solution I have is to disable my secondary monitor before I play any games. Of course this causes the aspect ratio of my video to be off so I am constantly enabling/disabling my secondary monitor. To make this even more annoying the confirmation dialogue for this always opens on my secondary screen which is usually off. I'v posted this problem 3X to this forum and never get a reply so best of luck you you!

Amarok suggests you might be a kde user, which makes it much less likey to be a window manager problem.

I have noticed some games actually work correctly. Starcraft using the latest wine seems too, doom 3 current patch is ok, but urban terror and quake 4 (latest) both have the problem. Savage is even worse, and that doesnt even let you move the mouse over to get the rest on screen.

Currently i have urban terror and quake IV running in windowed mode, using devilspie to undecorate/fullscreen/on top them which kind of hacks over the bug, but that limits my choice of window manager to metacity as thats the only one i can find that works correctly, compiz for instance just fails horrifically in a gaming environment.

Hopefully when xrandr 1.2 support is implemented it will be possible to script the monitor deactivation better to work aroud this issue, i would do that now using the nvidia-settings tool, but that ends up making my gnome panels cover 2 screens, and window maximisation etc. cover both screens.

When using twinview, the games Planet Penguin Racer, Nexuiz, VDrift and Slune, when in fullscreen, appear at an offset of half the screen to the right on the primary monitor. They all seem to use the metamode 1024x768,NULL because the left monitor turns off.

The game TORCS, when in fullscreen, appears fine on the left monitor while the right monitor stays on.

Screen savers usually appear on both monitors as one screen, having the point between the monitors as the center. I haven't seen any problems with screensavers.

I've had exactly the same problem way over a year ago when starting neverwinter nights fullscreen. There was at least one larger thread about the issue back then, maybe you can still dig it out.

What solved the problem for me was switching the displays: primary monitor on the left, secondary on the right using RightOf.

You could try using the 'UseDisplayDevice' option to redefine your primary screen - I never tested that though, since that option wasn't available back then. Consult the manual and try.

I suspect the problem might be solved by manually switching to a single-screen-resolution before starting the game (or writing a small script to do so), but actually I never tried that.

Right now I'm always spawning a second X server for games, to prevent game crashes/lockups from killing my workspace. Spawning a second X server that's configured without TwinView is another viable option. Basically you put a second xorg_game.conf into /etc/X11/, then create a small script that starts the game, copy or link it to ~/.xinitrc, then run
XORGCONFIG=xorg_game.conf startx -- :1
Don't forget to remove the ~/.xinitrc afterwards, or the next day you'll be booting straight into quake 3 instead of your desktop environment

I use the "UseDisplayDevice" in order to get the login screen to show up on my primary monitor, and for that it works. But my dialog confirmation boxes always show up on the wrong screen as well as the full screen opengl problem. If twinview was just not capable of doing dual monitor successfully I was would accept that. But the idea that this works if the primary monitor is on the left but not the right is absolute crap. What am I supposed to do, buy a new desk to fit my video card? Searching through the thread history it seems this problem is rarely reported, and when it is there is never a suggestion by nvidia as to a possible fix. Some of the threads have suggestions in them by users that are basically hacks in an attempt to work around the problem. It makes me wonder if either very few people have their primary monitor on the right, or I am doing something incredibly wrong and just missing the obvious.

Yeah, it definately works fine with primary on the left, but thats just not the way i work, and im not changing my whole desk layout/years of experience with it this way just to workaround a driver bug for some games.

I guess if this has been reported before without fixes then one isnt going to be forth coming, unless the work for xrandr 1.2 really sorts all this out (which is what i'm hoping) and lets the engineers get a chance to play with the twinview code some more. Hopefully the nouveau driver will get better quickly (it seems to be developing at a lightning pace) as i know they are taking the multiscreen/xrandr 1.2 stuff very very seriously. Just having multiple options for 3d drivers will be nice anyway, although all in all the nvidia produced one is very very good.

Added note, i have a suspicion the bug only exhibits in games that use the XF86Vidmode extension as oposed to the Xrandr extension to do resolution changes, which will be anything using sdl (from what dates i have no idea), and im not sure what newer sdl does in this regard. Wine for instance seems to do randr + wm hints for fullscreen, which actually is working well, but i dont know for certain the details of other apps. If i get some time i might write some test programs doing mode switching in a variety of ways, so we have a testbed we can work with on this.

Added note, i have a suspicion the bug only exhibits in games that use the XF86Vidmode extension as oposed to the Xrandr extension to do resolution changes, which will be anything using sdl (from what dates i have no idea), and im not sure what newer sdl does in this regard. Wine for instance seems to do randr + wm hints for fullscreen, which actually is working well, but i dont know for certain the details of other apps. If i get some time i might write some test programs doing mode switching in a variety of ways, so we have a testbed we can work with on this.

FYI: For me it is not just games. Some 3D screensavers and amarok plugins behave the sane way. Thanks for responding.

I have this same issue running twinview And I did the only thing I could and that was edit xorg.conf to have the orientation set to RightOf. If anyone else finds a better solution pls post it. Thx y'all.